1. Field of the Invention
The present invention relates to a recording material for back printing.
2. Description of the Related Art
As shown in FIG. 1, a recording material for back printing 10 generally has a layered structure in which the following are built up in order: a transparent substrate 1 made of PET or the like; an ink absorbing layer 2; and a porous ink transmitting layer 3 comprising a filler dispersed in a binder resin.
With the recording material for back printing 10, an ink image is formed on the surface of the ink transmitting layer 3 by means of an ink jet printer or the like, and this ink image permeates through the ink transmitting layer 3 and is held by the ink absorbing layer 2. The ink image held in the ink absorbing layer 2 is viewed from the side of the transparent substrate 1.
However, with a printed article obtained by forming an ink image on a conventional recording material for back printing 10, there is a problem that if the printed article is used, for example, superposed on the back of a glass plate and water sticks to the ink transmitting layer 3 through dew condensation or the like, then this water will permeate through the ink transmitting layer 3 to the ink absorbing layer 2, causing the ink absorbing layer 2 to swell and move into the porous cavities in the ink transmitting layer 3, with the result that the transparent appearance and the color tones of the image, and so on, change. Furthermore, the swelling of the ink absorbing layer 2 will cause the adhesive strength between the ink absorbing layer 2 and the ink transmitting layer 3 to drop, in some cases leading to the ink transmitting layer 3 peeling away from the ink absorbing layer 2.
Moreover, there is also a problem that the ink transmitting layer 3 is easily scratched because it is porous.
In view of such problems, objects of the present invention are to increase the strength of the ink transmitting layer in a recording material for back printing, and to prevent the transparent appearance and the color tones of the image, and so on, from changing, when water sticks to the ink transmitting layer.
The inventors of the present invention discovered that by crosslinking the ink transmitting layer, the ink transmitting layer becomes stronger, and, moreover, the effects of crosslinking the ink transmitting layer extend at least as far as the region of the ink absorbing layer on the ink transmitting layer side, meaning that the phenomenon, in which the ink absorbing layer swells and moves into the porous cavities in the ink transmitting layer, can be suppressed.
The present invention thus provides a recording material for back printing that comprises: a transparent substrate; an ink absorbing layer that is provided on the transparent substrate; and a porous ink transmitting layer that is provided on the ink absorbing layer and comprises a binder resin and a filler dispersed therein, wherein the ink transmitting layer is crosslinked.